DISK DRIVER CLUSTER MANAGEMENT OF TIME SHIFT BUFFER WITH FILE ALLOCATION TABLE STRUCTURE

• US 20070168601A1
• Filed: 02/27/2007
• Published: 07/19/2007
• Est. Priority Date: 12/05/2001
• Status: Active Grant

• Current Assignee: Magnolia Licensing LLC (IP Edge LLC)
• Original Assignee: Scientific-Atlanta LLC (Cisco Systems, Inc.)
• Inventors: Plourde, Harold
• Granted Patent: US 7,779,181 B2
• Time in Patent Office: Days
• US Class Current: 711/112
• CPC Class Codes: G06F 16/10 File systems; File servers
• CPC Class Codes: G06F 16/40 of multimedia data, e.g. slideshows comprising image and additional audio data retrieval of still image data G06F16/50; retrieval of audio data G06F16/60; retrieval of video data G06F16/70
• CPC Class Codes: G11B 2220/2516 Hard disks
• CPC Class Codes: G11B 27/034 on discs G11B27/036, G11B27/038 take precedence
• CPC Class Codes: G11B 27/105 of operating discs
• CPC Class Codes: G11B 27/329 on a disc [VTOC]
• CPC Class Codes: H04N 21/4147 PVR [Personal Video Recorder] H04N5/76 takes precedence ; arrangements for broadcast with accumulation-type receivers H04H20/40
• CPC Class Codes: H04N 21/4334 Recording operations recording of a television signal H04N5/76; arrangements for recording or accumulating broadcast information or broadcast-related information H04H60/27
• CPC Class Codes: H04N 21/485 End-user interface for client configuration
• CPC Class Codes: H04N 5/76 Television signal recording
• CPC Class Codes: H04N 5/765 Interface circuits between an apparatus for recording and another apparatus
• CPC Class Codes: H04N 5/775 between a recording apparatus and a television receiver
• CPC Class Codes: H04N 5/781 on disks or drums
• CPC Class Codes: H04N 5/85 on discs or drums
• CPC Class Codes: H04N 9/8042 involving data reduction
• CPC Class Codes: Y10S 707/99943 Generating database or data structure, e.g. via user interface

Abstract

A file allocation system for a hard disk drive includes a memory with driver logic and a processor configured with the driver logic to receive a request to allocate hard disk space of a defined size for a buffer file. In some embodiments, the processor is configured with the driver logic to allocate clusters for the buffer file from a plurality of clusters on the hard disk, wherein the clusters for the buffer file store media content instances. In some embodiments, the processor is configured with the driver logic to designate a portion of the clusters of the buffer file for at least one non-buffer file such that the non-buffer file is permitted to share the portion of the clusters of the buffer file with the buffer file.

Claims

1. A computer readable storage medium comprising:

a file allocation table, said file allocation table comprising;

a first data structure comprising file list entries for files, wherein the file list entries include clusters allocated for each of the files; and

a second data structure comprising cluster list entries for the clusters, wherein the cluster list entries identify the clusters and a quantity of the files that simultaneously share each one of the clusters.

2. The computer readable storage medium of claim 1, wherein the file list entries further include a filename for each of the files and starting and ending sectors of each of the files.

3. The computer readable storage medium of claim 1, wherein the quantity of the files that share each one of the clusters is tracked in a file sharing counter.

4. The computer readable storage medium of claim 3, wherein the file sharing counter can have values of zero to signify that a corresponding cluster is available to be written to, values of one to signify that the corresponding cluster is used for a buffer file, and values greater than one to signify that corresponding clusters are to be used for permanent recordings.

5. The computer readable storage medium of claim 1, wherein the cluster list entries are updated such that a buffer file of clusters is limited to a substantially constant buffer file size, such that when the buffer file approaches a full status, a cluster storing the oldest media content is first deallocated from the buffer file and a new cluster is correspondingly allocated to the buffer file.

6. A computer readable storage medium comprising a device driver comprising:

logic configured to allocate clusters for a buffer file for buffer space on a disk and to cause media content instances to be written to the buffer space;

logic configured to limit the buffer file to a substantially constant buffer file size, such that when the buffer file approaches a full status, a cluster storing the oldest media content is first deallocated from the buffer file and a new cluster is correspondingly allocated to the buffer file; and

logic configured to maintain the buffer space as substantially constant in size by autonomously and automatically removing buffer space clusters designated for a permanent recording and replacing the removed buffer space clusters with replacement clusters.

7. The computer readable storage medium of claim 6, wherein the buffer space clusters designated for the permanent recording are permitted to be simultaneously shared among the buffer file and a file for the permanent recording.

8. The computer readable storage medium of claim 7, wherein the logic is further configured to use a file allocation table.

9. The computer readable storage medium of claim 8, wherein the file allocation table includes a first data structure comprising a list of the clusters for each of the files, and a second data structure comprising a list of the clusters located on the disk and a file sharing counter of how many of the files share each of the clusters.

10. The computer readable storage medium of claim 9, wherein the logic is further configured to increment the file sharing counter when the number of the files that are shared are increased and decrement the file sharing counter when the number of the files that are shared are decreased.

11. The computer readable storage medium of claim 7, wherein the logic is further configured to generate normal play time for each one of the files to track locations in each of the files and to track locations of media content instances.

12. The computer readable storage medium of claim 6, wherein the logic is further configured to generate normal play time for write operations and read operations to the disk.

13. A computer readable storage medium comprising a file allocation system for a hard disk drive comprising:

logic configured to receive a request to allocate hard disk space of a defined size for a buffer file;

logic configured to allocate clusters for the buffer file from a plurality of clusters on the hard disk, wherein the clusters for the buffer file store media content instances;

logic configured to designate a portion of the clusters of the buffer file for at least one non-buffer file such that the non-buffer file is permitted to simultaneously share the portion of the clusters with the buffer file; and

logic configured to limit the buffer file to a substantially constant buffer file size, such that when the buffer file approaches a full status, a cluster storing the oldest media content is first deallocated from the buffer file and a new cluster is correspondingly allocated to the buffer file.

14. The computer readable storage medium of claim 13, further comprising logic configured to maintain a file sharing count for the clusters of the buffer file, such that the clusters with the file sharing count greater than one are removed from the buffer file.

15. The computer readable storage medium of claim 13, further comprising logic configured to remove from the buffer file the portion of the clusters that are shared by the buffer file and the non-buffer file and designating said previously shared portion as a portion of non-buffer file clusters.

16. The computer readable storage medium of claim 15, further comprising logic configured to replace the removed clusters with replacement clusters for the buffer file to maintain the defined size of the disk space for the buffer file as substantially constant.

17. The computer readable storage medium of claim 13, further comprising logic configured to use a first data structure comprising list entries for the buffer file and the non-buffer file, wherein the list entries include filenames, the clusters allocated for the buffer file and the non-buffer file, and starting sectors and ending sectors for the non-buffer file.

18. The computer readable storage medium of claim 13, further comprising logic configured to use a second data structure comprising list entries for all of the clusters, wherein the list entries include the identities of each one of the clusters and a quantity of all of the hard disk files that share each one of the clusters.

19. The computer readable storage medium of claim 13, further comprising logic configured to write the media content instances to the clusters of the buffer file and, for scheduled recordings, the clusters of the non-buffer file.

20. The computer readable storage medium of claim 19, further comprising logic configured to return an application for normal play time values corresponding to the media content instances locations, the buffer file and the non-buffer file locations on the disk space that the media content instances are written to, and a current write location upon receiving an update request from an application.